The question is simple, what is better for avoiding of non-appropriated memory using? For example, let's say that we've a String s = "Test" and we'd like to add 1 to it so it becomes Test1. We all know that s gets a memory location and if we use StringBuilder, Test1 will get a new memory address or it'll remain at s's place, and what if we use concat?
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Anthino Russo
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Maybe [this post](https://stackoverflow.com/questions/1532461/stringbuilder-vs-string-concatenation-in-tostring-in-java) could be helpful. – 0xCursor Oct 04 '18 at 14:14
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Related : https://stackoverflow.com/questions/47605/string-concatenation-concat-vs-operator – alain.janinm Oct 04 '18 at 14:21
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Always search Stack Overflow thoroughly before posting. – Basil Bourque Oct 04 '18 at 14:31
1 Answers
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One line concatenations are optimized and converted to StringBuilder under the hood. Memory wise is the same thing, but the manual concatenation is more concise.
// the two declarations are basically the same
// JVM will optimize this to StringBuilder
String test = "test";
test += "test";
StringBuilder test = new StringBuilder();
test.append("test");
On the other hand, if you don't do trivial concatenations, you will be better off with StringBuilder.
// this is worse, JVM won't be able to optimize
String test = "";
for(int i = 0; i < 100; i ++) {
test += "test";
}
// this is better
StringBuilder builder = new StringBuilder();
for(int i = 0; i < 100; i ++) {
builder.append("test");
}
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[for the record, some real numbers](https://stackoverflow.com/a/49466784/1059372) – Eugene Oct 05 '18 at 09:39